Grouted Seepage Cutoffs in Karstic Limestone

Four types of seepage cutoffs have been successfully utilized in limestone formations: open-cut excavated cutoffs, diaphragm wall cutoffs, secant pile cutoffs, and grouted cutoffs. After falling somewhat out of favor due to lack of success on some projects, recent advances in materials, procedures, and techniques have resulted in practitioners regaining confidence in grouting. This paper examines cutoff methods with respect to geologic compatibility and the issues, problems, and limitations for each type of cutoff. Four recent case histories of successfully grouted seepage cutoffs are discussed: the reservoir rim cutoff at Tims Ford Dam, Tennessee, the Patoka Lake spillway in Indiana, Wujiangdu Hydroelectric Project in China and a multi-material cutoff in an operating quarry in West Virginia.